(1) Field of the Invention
The present invention is directed to buoyant cable antennas. In particular, the present invention is directed to a new form of hybrid dual band buoyant cable antenna element suitable for underwater vehicle communication capable of providing performance suitable for very low frequency (VLF) reception and high frequency (HF) transmission and reception in a single antenna element.
(2) Description of the Prior Art
The buoyant cable antenna is one of several antennas currently in use for underwater vehicle communications. It consists of a positively buoyant insulated wire that floats on the ocean surface. It connects to the submerged underwater vehicle by means of a long length coaxial transmission line. It is used for communications primarily in the VLF through HF (10 kHz-30 MHz) frequency range. Using existing systems, VLF reception is best using a 100 ft antenna with a short circuit tip. However, HF performance is sacrificed when using this antenna. Conversely, HF performance is best achieved using a 50 ft antenna with an open circuited tip, but this configuration compromises VLF performance.
Currently, there is a need for a hybrid dual band buoyant cable antenna element suitable for underwater vehicle communication capable of providing performance for both VLF reception and HF transmission and reception in a single antenna element.